1/*
2 * Copyright 2014 Steffen Trumtrar <s.trumtrar@pengutronix.de>
3 *
4 * based on
5 * Allwinner SoCs Reset Controller driver
6 *
7 * Copyright 2013 Maxime Ripard
8 *
9 * Maxime Ripard <maxime.ripard@free-electrons.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 */
16
17#include <linux/err.h>
18#include <linux/io.h>
19#include <linux/module.h>
20#include <linux/of.h>
21#include <linux/platform_device.h>
22#include <linux/reset-controller.h>
23#include <linux/spinlock.h>
24#include <linux/types.h>
25
26#define NR_BANKS		4
27#define OFFSET_MODRST		0x10
28
29struct socfpga_reset_data {
30	spinlock_t			lock;
31	void __iomem			*membase;
32	struct reset_controller_dev	rcdev;
33};
34
35static int socfpga_reset_assert(struct reset_controller_dev *rcdev,
36				unsigned long id)
37{
38	struct socfpga_reset_data *data = container_of(rcdev,
39						     struct socfpga_reset_data,
40						     rcdev);
41	int bank = id / BITS_PER_LONG;
42	int offset = id % BITS_PER_LONG;
43	unsigned long flags;
44	u32 reg;
45
46	spin_lock_irqsave(&data->lock, flags);
47
48	reg = readl(data->membase + OFFSET_MODRST + (bank * NR_BANKS));
49	writel(reg | BIT(offset), data->membase + OFFSET_MODRST +
50				 (bank * NR_BANKS));
51	spin_unlock_irqrestore(&data->lock, flags);
52
53	return 0;
54}
55
56static int socfpga_reset_deassert(struct reset_controller_dev *rcdev,
57				  unsigned long id)
58{
59	struct socfpga_reset_data *data = container_of(rcdev,
60						     struct socfpga_reset_data,
61						     rcdev);
62
63	int bank = id / BITS_PER_LONG;
64	int offset = id % BITS_PER_LONG;
65	unsigned long flags;
66	u32 reg;
67
68	spin_lock_irqsave(&data->lock, flags);
69
70	reg = readl(data->membase + OFFSET_MODRST + (bank * NR_BANKS));
71	writel(reg & ~BIT(offset), data->membase + OFFSET_MODRST +
72				  (bank * NR_BANKS));
73
74	spin_unlock_irqrestore(&data->lock, flags);
75
76	return 0;
77}
78
79static int socfpga_reset_status(struct reset_controller_dev *rcdev,
80				unsigned long id)
81{
82	struct socfpga_reset_data *data = container_of(rcdev,
83						struct socfpga_reset_data, rcdev);
84	int bank = id / BITS_PER_LONG;
85	int offset = id % BITS_PER_LONG;
86	u32 reg;
87
88	reg = readl(data->membase + OFFSET_MODRST + (bank * NR_BANKS));
89
90	return !(reg & BIT(offset));
91}
92
93static struct reset_control_ops socfpga_reset_ops = {
94	.assert		= socfpga_reset_assert,
95	.deassert	= socfpga_reset_deassert,
96	.status		= socfpga_reset_status,
97};
98
99static int socfpga_reset_probe(struct platform_device *pdev)
100{
101	struct socfpga_reset_data *data;
102	struct resource *res;
103
104	/*
105	 * The binding was mainlined without the required property.
106	 * Do not continue, when we encounter an old DT.
107	 */
108	if (!of_find_property(pdev->dev.of_node, "#reset-cells", NULL)) {
109		dev_err(&pdev->dev, "%s missing #reset-cells property\n",
110			pdev->dev.of_node->full_name);
111		return -EINVAL;
112	}
113
114	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
115	if (!data)
116		return -ENOMEM;
117
118	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
119	data->membase = devm_ioremap_resource(&pdev->dev, res);
120	if (IS_ERR(data->membase))
121		return PTR_ERR(data->membase);
122
123	spin_lock_init(&data->lock);
124
125	data->rcdev.owner = THIS_MODULE;
126	data->rcdev.nr_resets = NR_BANKS * BITS_PER_LONG;
127	data->rcdev.ops = &socfpga_reset_ops;
128	data->rcdev.of_node = pdev->dev.of_node;
129	reset_controller_register(&data->rcdev);
130
131	return 0;
132}
133
134static int socfpga_reset_remove(struct platform_device *pdev)
135{
136	struct socfpga_reset_data *data = platform_get_drvdata(pdev);
137
138	reset_controller_unregister(&data->rcdev);
139
140	return 0;
141}
142
143static const struct of_device_id socfpga_reset_dt_ids[] = {
144	{ .compatible = "altr,rst-mgr", },
145	{ /* sentinel */ },
146};
147
148static struct platform_driver socfpga_reset_driver = {
149	.probe	= socfpga_reset_probe,
150	.remove	= socfpga_reset_remove,
151	.driver = {
152		.name		= "socfpga-reset",
153		.of_match_table	= socfpga_reset_dt_ids,
154	},
155};
156module_platform_driver(socfpga_reset_driver);
157
158MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de");
159MODULE_DESCRIPTION("Socfpga Reset Controller Driver");
160MODULE_LICENSE("GPL");
161